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Dumping trees to a console.

by BrowserUk (Pope)
on Oct 15, 2012 at 14:11 UTC ( #999091=CUFP: print w/ replies, xml ) Need Help??

Dumping trees to a terminal in a compact, readable form is an invaluable aid to developing and debugging tree-based algorithms. The following demonstrates a mechanism for doing this for array-based binary trees:

#! perl -slw use strict; use List::Util qw[ max ]; our $N; use enum qw[ LEFT RIGHT ]; sub _traverse { my( $code, $tree, $d, $w ) = @_; ref $tree->[LEFT] and $w = _traverse( $code, $tree->[LEFT], $d+1, $w ) or $code->( ++$w, $d, $tree->[LEFT] ); $code->( ++$w, $d,'^' ); ref $tree->[RIGHT] and $w = _traverse( $code, $tree->[RIGHT], $d+1, $w ) or $code->( ++$w, $d, $tree->[RIGHT] ); return $w; } sub traverse(&$) { _traverse( @_, 0, 0 ); } use enum qw[ WIDTH DEPTH NAME ]; sub dumpTree { my $tree = shift; my @g; traverse{ push @g, [ @_ ]; } $tree; my $width = max( map $_->[WIDTH], @g ); my $depth = max( map $_->[DEPTH], @g ); my @graph = map ' ' x $width, 0 .. $depth; substr $graph[ $_->[DEPTH] ], $_->[WIDTH], 1, substr($_->[NAME],0, +1) for @g; unshift @graph, (' ' x $width) x 2; for my $i ( reverse 0 .. $#graph ) { substr( $graph[$i-1], $-[1], $+[1]-$-[1], '/' . ' ' x (length( +$1)-2) . '\\' ), substr( $graph[ $i ], $-[2], 1, ' ' ) while $graph[ $i ] =~ m[(\S\s*(\^)\s*\S)]g; } my $n; for my $i ( reverse 0 .. $#graph ) { $n = $+[1]-$-[1], substr( $graph[ $i-1 ], $-[1]+1, $n-2, '_' x ($n-2)) while $graph[ $i ] =~ m[(/\s+\\)]g; } print for @graph, ''; return unless $N; my @names = map[ split '', reverse ], grep !/\^/, map $_->[NAME], +@g; print for map{ join( ' ', '', map pop @$_//' ', @names ) } 0 .. max( map scalar @$_, @names ); } my @a = qw[ alpha bravo charlie delta echo foxtrot golf hotel indigo juliet kilo mike november oscar papa quebec romeo sierra tango uniform victor whiskey xray yankee zulu ]; our $S //= 0; srand $S if $S; my $r; $r = int( rand $#a ), splice @a, $r, 2, [ @a[ $r, $r+1 ]] while @a > 1 +; @a = @{ $a[0] }; dumpTree( \@a );

A couple of examples:

C:\test>genBinTree -S=1 ___________ ___________/ \___ _______/ \_ _/ \ _____/ \_ _/ \_ _/ \_ z _/ \_ _/ \_ _/ \ / \ _/ \ / \ _/ \_ _/ \ _/ \ / \ _/ \ r s t / \ w x y _/ \ / \ / \ h / \ k m n / \ q u v / \ c d e f g i j o p a b C:\test>genBinTree -S=1 -N ___________ ___________/ \___ _______/ \_ _/ \ _____/ \_ _/ \_ _/ \_ z _/ \_ _/ \_ _/ \ / \ _/ \ / \ _/ \_ _/ \ _/ \ / \ _/ \ r s t / \ w x y _/ \ / \ / \ h / \ k m n / \ q u v / \ c d e f g i j o p a b a b c d e f g h i j k m n o p q r s t u v w x y z l r h e c o o o n u i i o s a u o i a n i h r a u p a a l h x l t d l l k v c p e m e n i c i a n l h v r t o t f e i i o e e a a b e r g f t s y k u a o l a r l g e m r e o r o o o k e i o o t b c a r r e e e t e m y r C:\test>genBinTree -S=1234567890123456789 _____________________ _______/ \_ _______/ \___________ _/ \___ _/ \ _____/ \ _/ \ / \_ / \___ f / \_________ q _/ \ v w _/ \ a / \_ g ___/ \ _/ \ u / \ z b _/ \ / \_____ p / \ t x y / \ e h _/ \_ r s c d / \_ _/ \ i / \ / \ o j k m n C:\test>genBinTree -S=123456789012345678 _______ ___/ \_ _/ \_ _/ \_______ / \_ / \_ / \ / \_________ a / \ d / \ g h i _/ \___________ b c e f _/ \ ___/ \_ _/ \ n _/ \ _____/ \ / \ m _/ \_ s ___/ \ z j k / \ / \ / \_ y o p q r t _/ \_ / \ / \ u v w x

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